<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<style>
	  section {display: flex;}
	  .left-side,
	  .right-side {width: 200px;background: #000000;}
	  .content {flex-grow: 1;background: #000000;}
	  
	</style>
	<body>
		<section>
		  <div class="left-side"></div>
		  <div class="content"></div>
		  <div class="right-side"></div>
		</section>
	</body>
</html>
<script type="text/javascript">
	var show=function(){
		var num=12
		 return function(){
			return num
		}
		
	}
	var a=show()()
	console.log(a);
	 
</script>